Among the existing impact resistant materials used hitherto, the polyurethane urea elastomer, first of all, has been widely used in various forms of molding on an industrial scale, but the elastomer in its actual application has suffered from disadvantages such as a high cost in manufacture, high specific gravity, and disproportionate relations among physical property, impact resistant effect, and recovery force.
Secondly, the microcellular foamed impact resistant material has also a recognized disadvantage in that, to decrease the change of impact resistant effect owing to the variation of outer temperature, the amine-substituted polyol which is made through the specifically complicated polymerization reaction, and aromatic vinyl monomer requiring high costs have been inevitably used. Further, in order to supplement the impact resistant effect, various kinds of fillers including asphalts and adhesives have been separately added in large amounts.
Under such disadvantages, the usual impact resistant foam led to increases in their specific gravities and costs. So, their practical usage has been reduced, and in the related fields, their application scope is quite limited.